In the conventional reserve battery cell, electrolyte is generally retained in a ampoule made of glass. However, the glass ampoule can be manufactured to have a size at least longer than a centimeter with a thickness greater than hundreds of μ. Further, the shape of the glass ampoule is limited to a cylindrical shape. Therefore, the conventional reserve battery cells can be manufactured at a large size only, and a relatively stronger power is required to mechanically destroy the ampoule. Hence, the conventional reserve battery cells have a drawback of being inapplicable to a small electronic system requiring activation of a super-slim battery with less power.